Fixed default invoker re-creation in debug mode, usage is now exposed correctly the user callback.
    There is still an issue with extension methods that will be fixed at a later point.
Various improvements for PSInvoke.
  - Added a fast path if parameters matches delegate signature.
  - Simplified the code, use MethodBinder argument conversion instead of a custom (and slower) one.
  - Reduced memory usage for PSInvoke.
Non-committed files from a previous merge?